SS 2

RESPIRATORY SYSTEM

The respiratory system is concerned with the intake of oxygen from the environment and entry into the body. Respiration is a biochemical activity in which glucose is broken down by a series of reactions in the cell to release energy. Respiration occurs in two phases:

1. External Respiration (breathing): this is the exchange of gases between the environment and the respiratory organs of living things
2. Internal, Tissue or Cellular Respiration is the oxidation of organic food substances within the cell to release energy in form of ATP.

Cellular respiration can be represented by the following equation:

C₆H₁₂O₆  +  6O₂    →   6CO₂   +  6H₂O  + Energy

TYPES OF RESPIRATORY SYSTEMS

1. Cell membrane/ Body surfaces/Skin: unicellular organisms such as Paramecium and Amoeba have a high surface area to volume ratio. Thus, they are able to carry out gaseous exchange by diffusion across the cell membrane. Some organisms such as earthworm and frog carry out gaseous exchange across the skin surface; this is known as cutaneous respiration. Their skin is usually moist so that oxygen and carbon (IV) oxide could dissolve and diffuse across the body surface. Their skin is also richly supplied with blood capillaries with transport the dissolved oxygen round the body.
2. Gills: are found in aquatic organisms; they could be external e.g. in larva of fish, tadpoles and Salamander OR internal as in most fishes e.g. Tilapia. Internal gills are found in gill chambers protected by the operculum (plural- opercula). There are four pairs of gills; each gill consist of a bony structure called gill arch. Soft filaments which are richly supplied with blood vessels are attached to the gill arch. The filaments absorb oxygen present in the water that flows over them. Gill rakers are also found on the gill arch; these filters off food from the water and prevents them from damaging the delicate gills.
3. Tracheal system: this is found in insects. Air enters and leave their bodies via openings on their body surface known as spiracles found in pairs at every segment of the insect’s body. The spiracles open to a network of tubes which extends throughout the body of the insect; these tubes are called tracheae which divide into smaller tracheoles that come I direct contact with the body cells of the insect
4. Lungs: this is used by all mammals and birds, most reptiles and some amphibians. Lungs are located within the thoracic cavity and consist of air sacs which provide a large surface area for gaseous exchange. The epithelium of the lungs is surrounded by a network of capillaries

RESPIRATORY SURFACES OF SOME ORGANISMS

1. Amoeba, Paramecium: Body surface (cell membrane)
2. Earthworm: Body surface
3. Fish: Gills
4. Insects: Spiracles and trachea
5. Amphibians (frogs and toads): Gills (tadpole stage), skin, mouth and lungs (adult stage)
6. Birds and mammals: Lungs
7. Plants: Stomata and lenticels

Characteristics of Respiratory Surfaces

1. They are thin-walled to shorten diffusion distance or for easy diffusion of gases
2. They have a large surface area to enhance/allow maximum diffusion of gases
3. They are moist to allow gas dissolve and diffuse through them
4. They are well ventilated for easy access to gases
5. They are highly vascularized i.e. they have an adequate supply of blood vessels for easy transport/circulation of gases

Mechanism of Respiratory Systems

1. Mechanism of gaseous exchange in lower animals e.g. Amoeba, Paramecium is by diffusion. Oxygen diffuses into the body while carbon(IV)oxide diffuses out through the cell membrane.
2. Mechanism of gaseous exchange in insects: Insects use the tracheal system for gaseous exchange. The terminal ends of tracheoles are in contact with cells in the body. Air is drawn in and out of the tracheae by compression and relaxation of the abdominal muscles
3. Mechanism of gaseous exchange in Annelids: Annelids such as earthworm carry out gaseous exchange by diffusion across the skin surface. Glands under the skin secrete mucus which keeps the skin moist. Oxygen dissolves in the moisture and diffuses across the skin into blood capillaries found near the skin.
4. Mechanism of gaseous exchange in Fishes: The fish use gills which are located on both sides of the head for gaseous exchange. Tilapia fish ventilates its gills by buccal pumping. The mouth opens while the floor of the mouth is lowered, at the same time the opercula are closed, water is then drawn into the mouth. When the floor of the mouth is closed, the floor of the mouth is raised and the opercula open, water containing dissolved oxygen passes through the gills. The dissolved oxygen is then absorbed by the capillaries on the gills and carried into the general blood circulation.    
   
5. Mechanism of gaseous exchange in Amphibians: the toads and frogs engage in cutaneous (skin), buccal (mouth) and gaseous exchange by the lungs. 

a.       Cutaneous (skin) respiration: the skin is thin, moist and well supplied with blood vessels. The skin is kept moist by slimy mucus secreted by the mucous glands. Oxygen diffuses through the moist skin into the blood vessels by diffusion. This occurs mostly when the amphibians are in the water.

b.      Buccal (mouth) respiration: the buccal cavity is lined with thin membrane lined with blood capillaries. While the mouth is closed and the nostrils opened, the floor of the mouth is lowered, air is drawn into the mouth. While the mouth remains closed oxygen diffuses into the blood capillaries and is carried to all parts of the body by the blood. At the same time, carbon(IV)oxide diffuses out into the buccal cavity. Thereafter, the nostrils are opened, the floor of the mouth is raised and the air containing carbon(IV)oxide and water vapour is passed out into the atmosphere.

c.       Respiration by lungs: during lung respiration, the nostrils are opened while the mouth is closed. While the floor of the mouth is lowered, air rushes in. When the floor of the mouth is raised, the nostrils and the mouth are closed and the glottis is opened, air is forced through the glottis into the lungs where oxygen diffuses into the capillaries of the lungs and carbon(IV)oxide diffuse out.

6. Mechanism of gaseous exchange in mammals: the respiratory system of mammals consists of the following-

a.       Nose: it warms and moistens the incoming air. Also, the mucus and hairs in the nostrils filter the incoming air.

b.      Pharynx: leads to the oesophagus and larynx (voice box). The epiglottis is situated close which prevents food from getting into the trachea by closing the glottis during swallowing.

c.       Larynx (voice box): is short and made of cartilage. Air enters into the trachea via the larynx.

d.      Trachea: is made of cartilage to prevent it from collapsing. It runs from the larynx and branches out into two bronchi (singular- bronchus)

e.       Bronchi: these are made of cartilage and consist of the right and left bronchus which leads to the right and left lungs respectively. The bronchi branches out into bronchioles which lead into alveoli (singular- alveolus)

f.        Alveoli: these are air sacs where gaseous exchange take place.

g.      Lungs: are spongy organs consisting of bronchioles, alveoli, a network of blood vessels and capillaries. It occupies the thoracic cavity between the shoulder and diaphragm. It is surrounded by an elastic pleural membrane.

       Gaseous exchange (breathing) in man consist of two stages- inspiration and expiration

1.      Inhalation (inspiration): this involves breathing in the air. When this happens, the chest cavity expands, the air pressure in the lungs decreases, the intercostal muscles contracts, the diaphragm contracts and flattens and the ribcage moves upwards and outwards.
2.      Exhalation (expiration): this involves breathing out air from the lungs to the atmosphere through the nostrils. When this happens, the chest cavity contracts, the air pressure in the lungs increases, the external intercostal muscles relax, the diaphragm relaxes and assumes a dome shape and the ribcage moves downwards and inward.

After exhalation, the air in the lungs is not completely expelled. The air left behind is called residual air (about 1.5 litres) while the volume of air taken in and expelled during normal breathing is called tidal air (about 0.5 litres). The lung capacity is the total volume of air in the lungs (about 5 litres). Vital capacity is the volume of air that can leave or enter the lungs during forced breathing (about 3.5 litres)

While the air goes into the alveoli, oxygen diffuses through the moist respiratory surface into the blood capillaries while carbon(IV)oxide diffuses out.

    7.      Mechanism of gaseous exchange in plants: though plants do not have special respiratory organs, oxygen and carbon(IV)oxide diffuse through openings on the leaves called stomata (singular- stoma) and openings on the stem called lenticels. The stomata are tiny pores on the epidermis of leaves bounded by two bean-shaped cells known as guard cells which possess chlorophyll for photosynthesis.

     The guard cells open when turgid and close when flaccid. The opening and closing of the stomata is controlled by osmosis.

    Gaseous exchange in the leaves of flowering plants: during darkness, oxygen from the atmosphere; diffuses through the stomata into the air spaces; of the mesophyll layer of the leaf; it dissolves in the moist surfaces of the cells; and then diffuses into the mesophyll cells; the carbon dioxide produced from these cells diffuses out;   through the stomata; during the day, oxygen diffuses out of the mesophyll of the leaf; to the atmosphere; carbon dioxide from the atmosphere; diffuses into the mesophyll of the cells

AQUATIC HABITAT

An aquatic habitat is a natural body of water in which certain organisms live naturally. There are three types of aquatic habitats:

1. Marine habitat (salt water habitat)
2. Estuarine habitat (brackish water habitat)
3. Fresh water habitat

MARINE HABITAT

Marine habitat is an aquatic habitat that contain salt water e.g. oceans, seas, lakes, sea shores.

Characteristics of marine habitat

1. Salinity: salinity of marine habitats is high, at about 35 parts of salt per thousand (35‰)
2. Size: size of marine habitats is very large
3. Density: density of marine water is high at about 1.028g/cm³; this causes organisms to float in it.
4. Pressure: the water pressure of marine habitat increases with depth at one atmosphere for every 10m. The pressure at the bottom is high.
5. Temperature: the temperature of marine habitats decreases with increase in depth. The temperature is about 30̊C at the top and 4̊C at the ocean floor.
6. Oxygen concentration: the oxygen content of marine water is highest at the top where atmospheric oxygen dissolves in the water and decreases with depth.
7. Hydrogen ion concentration (pH): marine water is alkaline with a pH of 8.0 - 9.0.
8. Light penetration: light penetrates the marine habitat to a depth of about 200m. This is due to water turbidity.
9. Marine habitats are usually affected by waves, ocean currents and tides.

Major Ecological Zones of Marine Habitat

1. Supratidal zone (splash zone): this is the exposed zone of the marine habitat; it is land where water splashes when waves break at the sea shore.
2. Intertidal zone (neritic zone): this zone is exposed at low tide and submerged at high tide.
3. Subtidal zone: is about 200m deep and constantly submerged by water.
4. Bathyal zone: this zone is about 3000m deep and is characterized by low light penetration
5. Abyssal zone: this zone is ab0ut 7000m deep. It is characterized by low temperature, low light penetration and high pressure
6. Hadal zone: this zone is up to about 10000m deep. It is characterized by no light penetration, very low temperature, high pressure and no photosynthetic activity.

On the basis of light penetration, marine habitat can be categorized into:

• i. Euphotic zone: has enough light penetration. Photosynthetic activities are high. Producers, consumers and decomposers are present here.
• ii. Disphotic zone: has dim light. Only consumers and decomposers are present.
• iii. Aphotic zone is the dark ocean bottom with no light penetration. Very few organisms are present here.

Distribution of organisms in marine habitat

Plants in the splash zone include grasses and Ipomea. Animals found here are sand crab and ghost crab.

Organisms in the intertidal zone include starfish, bivalve mollusc, mole crab, Limpet, barnacles, crabs, sea anemones, sea urchins, crabs and worms. Plants found here include Sargassum, sea lettuce and brown algae.

Organisms in the subtidal zone include starfish, polychaete worms, brown algae, red algae, prawn, shrimp, phytoplankton, zooplankton, squid, cartilaginous fish and bony fishes.

Other organisms of the deep ocean are shark, ray, sea catfish, croaker and angler fish.

Adaptive features of Organisms in Marine habitat

1. Star fish, bivalve mollusc, mole crab, sand crab and ghost-crab burrow into the soil to prevent being washed away by waves and to avoid desiccation during low tide.  They also possess gills for gaseous exchange in water and spongy tissue for gaseous exchange on land.
2. Star fish and bivalve mollusc have protective colouration like sand to prevent being detected by predators.
3. Limpets, barnacles, sea urchins and sea anemones attach themselves firmly to the rocks by the feet to prevent being washed away by waves
4. Barnacles have protective shell and enclose water in its shell to prevent desiccation.
5. Sea weeds possess hold fast for attachment and air bladder for buoyancy.
6. Algae, phytoplankton have small sizes to enable them float to reach light for photosynthesis.
7. Prawns and shrimps have gills for gaseous exchange, appendages for locomotion and exoskeleton to prevent water-loss from the body.
8. Bony and cartilaginous fish have gills for gaseous exchange, scales to prevent water-loss from the body and air bladder to adjust its depth within the water body.
9. Organisms of the benthic zone have fluorescent organs that produce light to attract their prey, have large mouths to capture their prey and can withstand high pressure and low oxygen concentration.

Food chain in marine habitat

Diatom → krill → squid → whale

Algae → limpet → whelk → seagull

ESTUARINE HABITAT

Estuarine habitat is a body of water where salt water from the sea mixes with fresh water from the land to produce brackish water. In Nigeria, estuaries are found in coastal zones of Lagos, Ondo, Edo, Delta, Akwa Ibom, Bayelsa, Rivers and Cross rivers.

Types of Estuaries

There are three types of estuaries

    a.  Bay: a little portion of sea water that enters into land to mix with fresh water.

    b.  Delta: where a river divides into many channels before entering the sea.

    c.  Lagoon: this is when sea/ocean water enters into land by means of a canal.

Characteristics of Estuarine Habitat

1. Fluctuations in salinity: the salinity of an estuary is lower at the mouth of the river and higher towards the sea
2. Turbidity: the turbidity of estuarine habitat increases especially during the rainy season due to the debris brought by flood water.
3. Shallowness of water: estuarine habitat is shallow due to deposition of debris by rivers. It is not as deep as marine habitat
4. High level of nutrients: estuarine habitat is characterized by high amount of nutrients
5. Low oxygen content: the oxygen content of an estuarine habitat is very low
6. Low species diversity: the species diversity of estuarine habitat is lower compared to that of marine habitat.

Distribution of Organisms in Estuarine Habitat

Plants in the estuary are phytoplankton, algae and epiphytic plants, Spartina, Salicornia, sedges, bulrush, saltgrass, Thalassia, red mangrove (Rhizophora racemosa), white mangrove (Avicennia nitida).
The animals are oysters, anemones, clams, crabs, lobster, shrimps and salmon fish

Adaptive Features of Organisms in Estuarine Habitats

1. Planktons / Diatoms possess air spaces in their tissues for buoyancy so as to reach light. They also have rhizoids/false feet for attachment to rocky shores
2. Algae possess chlorophyll for photosynthesis and air bladder for floating.
3. White mangrove possess breathing root (Pneumatophores) for exchange of gases.
4. Mosquito larva has breathing trumpets for gaseous exchange
5. Mudskipper fish have fins adapted for crawling when on land and swimming when in water
6. Worms have strong protective and impermeable covering against high salinity.
7. Crabs burrow fast into the mud to escape predators, strong waves or tides.

Food chain in Estuarine habitat

Detritus → shrimp → Salmon

Detritus → worms → snail → bird

FRESH WATER HABITAT

Fresh water habitat is an aquatic habitat that contain very low level of salinity e.g. rivers, springs, streams, lakes.

Characteristics of freshwater habitat

1. Low salinity: freshwater habitats contain no significant amount of salt
2. Small size: the body of freshwater habitats are small compared to marine habitats.
3. Variation in temperature: the temperature of freshwater habitat varies with depth and season. The temperature at the top is slightly higher at the top than at the bottom. The temperature during the hot season is also higher than the temperature during the cold season.
4. Shallow depth: freshwater habitats are usually shallow; this allows light penetrate through to the bottom.
5. High concentration of oxygen content: the concentration of oxygen in freshwater habitats is high and evenly distributed round the water body.
6. Seasonal variation: some rivers dry up during the dry season and increases in volume during the rainy season.
7. Currents: currents are present in freshwater which affects the distribution of gases and nutrients.

Types of freshwater habitats

There are two types of freshwater habitats on the basis of their mobility:

1.  Lentic freshwater: these are standing or stagnant water e.g. ponds, pools, lakes, swamps, dams
2.  Lotic freshwater: these are running waters which flow continuously in one direction e.g. rivers, streams, springs

Major Ecological Zones of Freshwater Habitats

Lentic freshwater habitat is divided into two zones:

a)  Littoral zone: this is the shallow part of the freshwater habitat. It contains several plants and animals.

b)  Benthic zone: this is the deepest part of the freshwater habitat. It does not have as much plants as littoral zone.

Lotic freshwater is also divided into two zones:

    a)  Pool zone: this is where the rate of water flow is slow and calm

    b)  Rapid zone: this is where the speed of water flow is very fast. 

Distribution of Organisms in a Freshwater Habitat

Some of the organisms found in the littoral zone of the freshwater habitat include Spirogyra, Chlamydomonas, water lettuce, water fern, duckweed, diatoms, reeds, sedges, water fleas, water snails, water skater, ducks, frogs, toads, tadpoles, hydra, snakes, crocodiles, waterbuck and hippopotamus.

Organisms found at the benthic region of freshwater habitat include water lily, ferns, commelina, hydra, Tilapia fish, mud fish, cat fish, leech, pupae of mosquito, crayfish, water snail, water scorpion, water boatman and water bug.

Adaptive features of organisms in freshwater habitat

1. Water hyacinth and water lily have air bladders, intercellular space and light weight that enable them float in the water. They also have broad leaves that helps in absorbing sunlight for photosynthesis.
2. Spirogyra has mucilaginous cover which protect them in water.
3. Water lettuce has hairs on their leaves which help them to trap air and enable them to float
4. Water boatman carries hair bubbles with it to the bottom of the pond for respiration under water
5. Water skater has long legs with which it skates on water surface
6. Lungfish carries out gaseous exchange with gills under water and when the river dries out, it burrows into the soil and begin to use lungs

Food Chain in Freshwater Habitat

Algae → Tadpole → Dragonfly larva → water stick insect

TERRESTRIAL HABITAT 

Terrestrial habitat refers to life on land. The nature of soil, rainfall and temperature are the major factors affecting the nature of terrestrial habitat.

Types of Terrestrial habitat

1.  Marsh 
2.  Rain forest 
3.  Savanna or grass land  
4.  Arid land 

MARSH HABITAT

 A marsh is a lowland habitat which is flooded at all times and in which grasses and shrubs grow but when trees are found there, it is called a swamp. While a marsh is a terrestrial habitat, it represents in many ways, a transitional habitat between the aquatic and terrestrial.

Formation of Marshes

Marshes are usually formed near rivers or other bodies of water such as lagoons. During rainy seasons, the river over flows its banks and its water may flood the adjoining land, the flooded land receivers additional water from rainfall. The land absorbs some or all of such water until it becomes saturated, leaving a layer of water lying on the surface. In the dry season, some of the water covering the marsh – evaporates, leaving pools of water separated from one another by patches of land.

 Marshes can also be formed when ponds and lakes are filled up with soil from the surroundings and organic debris from plants causing water logging. Marsh formation is a gradual process where an aquatic habitat is transformed into wet land.

TYPES OF MARSHES

 There two major types of marshes. These are fresh water marsh and salt water marsh.
FRESH WATER MARSH

 Fresh water marshes occur on land, just beyond the limit of the salt water marsh and beyond the areas influenced by tide. In this area, fresh water from rivers over flows the river banks to flood the adjoining lowland resulting in the formation of fresh water marsh.

SALT WATER MARSH

 In Nigeria, salt water marshes are found in a belt along the Atlantic Coast (Costal area) which is influenced by the tide, because the water along the coast is salty, it mixes up with fresh water from rivers to brackish water. In dry season, the volume of river water is relatively small, but in the rainy season, it is large. This large volume of river water mixes together with tidal seawater in estuaries, creeks and lagoons, filling them up and causing them to overflow their banks.

CHARACTERISTICS OF MARSHES

1.  Nature of Soil: The soils in marshes are wet, soft, water logged and poorly aerated.
2.  Lowland Habitat: the marsh is usually a lowland habitat which often enhance flooding and water logging.
3.  High Flood: the ground of marsh is often folded most of the time.
4.  Presence of stagnant water: stagnant water is often noticed in marshes especially during dry season. In raining season, the whole land is highly flooded.
5.  Presence of organic matter: As a result of fallen leaves, dead plants and animals, lots of organic matter are always present in marshes.
6.  High rate of organic decomposition: the decay of organic matter takes place in large scale in a marsh and this causes a decrease in oxygen content of the water. Lots foul smelling gases such as hydrogen sulphide and methane are usually experienced in marshes.
7.  High relative humidity: the relative humidity of the atmosphere around the marshes is usually very high.

DISTRIBUTION OF PLANTS AND ANIMALS IN MARSHES

Within marshes, different conditions such as the water depth, duration of flooding and level of salinity affect the distribution of organisms.

The dominant vegetations in marshes consist of soft stemmed plant like grasses, rushes and reeds. Animals and plants commonly found in marsh habitat are water lettus (pistia), sword grasses, duckweed water lilies, horn wort, sedges, white mangrove, red mangrove and raphia palm, mud skippers, hermit crabs, bloody clam, lizard, crocodile and cyrosperma (waqter arum).

These animals and plants are classified into two categories such as fresh water marsh and salt water marsh.

FRESH WATER MARSHES
The plants found freshwater marshes include emergent such as bulbrushes, cattails and arrowheads, submergents such as pondweeds, floating plants such as water lilies, duckweeds and bladder worts.
 Examples of animals found in fresh water marshes are:
 Crustaceans: such as barnacles, crabs, clams and shrimps.
 Mammals such as beavers, muskrats, river otters, raccons marsh rabbits and opposums.
 Water birds like egret, geese, ducks, herons and flamingos
 Insects such as marsh flies, horseflies and mosquitoes
SALT WATER MARSHES

Vegetation is the smooth cord grass, spartina. It is one of the most salt – tolerant plant. Further in land, where the high marsh is, plants such as the salt grass, saw grass and black needle rush grows.

The salt marshes support a diversity of animals which include:
 Invertebrates such as clams, shellfishes, shrimps and oysters
 Reptiles such as saltmarsh snakes and diamond back turtile
 Amphibians such as frogs and salamanders
 Birds such as the great blue herons and clapper rails
 Mammals such as muskrats, raccoon, rabbits and river offers

ADAPTIVE FEATURES OF MARSH ORGANISMS.

1.  Marsh grasses e.g. Spartina grows long and hollow rhizomes as well as fine roots to hold on to the soft substratum.
2.  Possession of long and narrow leaves which bend with changing tides and strong wind.
3.  Possession of special glands to secrete excess salts
4.  Plants possess interconnecting air passages that draw air form the leaves to the stem and roots which are submergent in mater.
5.  Possession of hollow or spongy stem with air space to adopt to low oxygen.
6.  Some plants possess succulents stem to dilute concentrated salt.
7.  Plants adopt to the standing water for relatively long period of time to able to survive at low oxygen level.

ANIMALS

1.  Crabs have gills that enable them to temporarily store dissolved oxygen
2.  Fiddle crabs burrow themselves in the muddy grounds when the tide comes in, to avoid being washed away by the water.
3.  Wading birds possess a long, curved beak which is used to probe the mud for food during low tide.
4.  Some animals adopt to nomadic lifestyle (i.e moving up to higher grounds during high tides and returning to lower areas) to hunt and feed only during low tides.

FOOD CHAIN IN MARSH HABITAT

 Detritus → Worms → Fishes

 Flowering plants → Insects → Frogs → Crocodiles

 Humus → Earthworms → Frogs → Snakes

 Detritus → Shrimps → Snake → Heron

FOREST HABITAT

The forest is an extensive community of plants dominated by trees. The distribution of the organisms in the forest is determined by rainfall, temperature and humidity.

Characteristics of a Forest

1.  Presence of tall trees
2.  Presence of broad leaves
3.  Presence of buttress roots
4.  Existence of canopies
5.  The trees exist in strata, storeys or layers
6.  The trees have thin barks
7.  Presence of epiphytes
8.  Presence of fallen leaves on the ground

Strata in the Forest

The forest vegetation has plants which are naturally arranged in layers:

1.  Emergent layer: the tallest trees of a tropical rain forest are found in the emergent layer. The trees in this zone have heights in the range of 40m and above. The crowns of the trees in this layer do not normally touch others e.g. Iroko, Obeche, African walnut, Mahogany, Teak, Ebony.
2.  Canopy layer: these are directly beneath the emergent. The trees are medium in size and have broad crown-like branches that interlock to form a continuous canopy
3.  Understorey layer: this comprise of short trees with height ranging from 10m – 15m. The amount of light in this zone is low, thus limiting the number and type of plants found here.
4.  Shrub layer: a shrub is a woody plant which is smaller than a tree and has several branches arising at or near the ground. The plants in this region
5.  Ground layer: the forest floor is dark and humid. It constitutes organisms such as fungi, fern, mosses and sparse grasses.

Distribution of Organisms in the Forest

Plants found in the forest include Iroko, Mahogany, African walnut, Obeche, Oil palm, Ferns, Orchids, Lianas, mosses, Lichens, fungi and mistletoe.

Most of the animals in the forest are arboreal animals e.g. bats, monkeys, snakes, lizards, tree frogs and chameleon. Other animals are soil dwelling e.g. earthworm, beetle while other animals live among litters in the ground e.g. snail, millipede and ants.

Adaptive Features of Organisms in the Forest Habitat

1.  The venus fly trap is well adapted to catch insect prey; the leaves snap shut when an insect touches the hairs inside.
2.  Iroko, mahogany and obeche have strong tap root system and buttress root for anchorage and support for the weight of the plants.
3.  The trees e.g. African walnut have broad leaves which aid photosynthesis and transpiration.
4.  Orchids are epiphytes which possess mechanism for storing water and absorbing moisture from the air while growing on tree branches.
5.  Mistletoe are plant parasite with haustoria that can penetrate the stem of a plant and feed directly from the manufactured food from the phloem tissues of the host plant.
6.  Monkeys have strong limbs for climbing and jumping on trees and prehensile tail for hanging on tree branches.
7.  Green snakes have protective colouration which makes it difficult to be detected by predators. They also have elongated bodies with grasping scales for winding about trees.
8.  Chameleon has prehensile tail and opposable digits for grasping. It also has protective colouration for camouflage.
9.  Apes move in groups or herds to protect themselves.
10.  Tree frogs have sticky pads that help them to grasp onto tree branches.

Food Chain in Forest Habitat

Green plants → Caterpillar → Lizard → Snake

Green plants → Grasshopper → Toad → Hawk

Banana tree → Monkey → Jaguar